An Introduction to Vedic Mathematics

Vedic mathematics is the ancient name of mathematics that was rediscovered in twentieth century. Vedic Mathematics has a unique technique of calculations based on 16 Sutras.  

A simple digital multiplier (referred henceforth as Vedic multiplier) architecture based on the Urdhva Triyakbhyam (means vertically and Cross wise) Sutra is explained. Urdhva – Triyakbhyam is the general formula which is applicable to all cases of multiplication.

The beauty of Vedic multiplier is that here partial product generation and additions are done concurrently or simultaneously. Hence, it is well adapted to parallel processing. The feature makes it more attractive for binary multiplications. This in turn reduces delay and reduces complex calculations into simple one. In most of the dsp applications, the critical operations are multiplication and accumulation.

The method is explained below for two, 2 bit numbers A and B where A = a1a0 and B = b1b0. Firstly, the least significant bits are multiplied which gives the least significant bit of the final product (vertical). Then, the LSB of the multiplicand is multiplied with the next higher bit of the multiplier and added with, the product of LSB of multiplier and next higher bit of the multiplicand (crosswise). The sum gives second bit of the final product and the carry is added with the partial product obtained by multiplying the most significant bits to give the sum and carry. The sum is the third corresponding bit and carry becomes the fourth bit of the final product. The 2X2 Vedic multiplier module is implemented by four input AND gates & two half-adders.
 

method for 4x4 Vedic multiplier 

 

It is found that the hardware architecture of 2x2 bit Vedic multiplier is same as the hardware architecture of 2x2 bit conventional Array Multiplier.

Hence it is concluded that multiplication of 2 bit binary numbers by Vedic method does not made significant effect in improvement of the multiplier’s efficiency. The 4x4 bit Vedic multiplier module is implemented using four 2x2 bit Vedic multiplier modules as shown above. 

In 4x4 multiplications, A= a3 a2 a1 a0 and B= b3 b2 b1 b0. The output line for the multiplication result is – s7s6s5s4 s3s2 s1 s0 and carry is ca2ca3.The main advantage behind this architecture is that the area needed for Vedic multiplier is very small as compared to other multiplier architecture. 

hardware architecture of 4x4 multiplier

Tags : Vedic mathematics     Vedic Multiplier      Vedic Methods    Introduction to Vedic Mathematics

Author - Hemika Yadav

(Intern at Silicon Mentor)

Writing Ph.D Thesis/Dissertation - The first phase

Idea of writing PhD thesis brings a lot of confusions, misconceptions and unanswered questions in the mind of PhD aspirants. Some of the difficulties they come across are related to the selection of the topic, starting the study, or time allocation for different phases of the thesis. One can handle these easily if one is determined and familiar with the current and recent topics and trends being followed in his field of interest. In this article the first step of thesis writing has been discussed with do’s and don’ts which one should follow in this phase.

Topic selection

 Topics should be selected after gaining a brief idea of recent work being carried out in the concerned domain and where it overlaps to your academic interests. There are many sources and ways which help in this.

-  Attending conferencing and referring to topic specific journals proves to be helpful in choosing a current and recent topic of interest.

-  Talking to colleagues and fellow students about their research and attending their presentations.

-  Interacting with your guide is a good idea as he has got more experience; it helps in at least Rough Idea of the Process.                       

Even in the study phase keep in mind that that you have to do research in an area not on an area. So, only reading papers and doing nothing effectively is researching on area and it leads to depression as every area seems to have been thought of already.

The other thing one should do is to take non-realistic topic as research takes time. Even if you have a lot of time to spare, never choose a topic without doing a deep study of feasibility and the problem your research will solve in the area.

At last the final suggestion is that, never look for the right topic or the hot topic as there is no right topic and your appropriate topic should be blend of your interest and current problems in the area and what’s hot today may be ice cold tomorrow and your research is going to take time.

Let's take a Video Tutorial for "  PhD Thesis Planning and Writing "

Tags :    PhD Thesis          PhD Research Projects      Dissertation Topics        PhD Research Topics

Author - Krishan Verma

(Research Associate at Silicon Mentor)

Role of SPICE Simulator in Analog/Digital VLSI Design

As we are entering in the great era of electronics world so we need tools and techniques which can makes our work easier. One of them is SPICE.

SPICE is the acronym of “simulation program with integration circuit emphasis”. As the name suggests it is general purpose software for the simulation of different circuits. SPICE used for EDA (electronic design automation).

Now let us discuss about process of using SPICE for simulation. In this tool, circuit file is the input. For creating circuit file, programming or directly schematic can be used. Programming may be simple code in “c language” or in any other computer language while schematic is drawn according to desire circuitry in SPICE schematic window. There is library present in SPICE tool which contains the basic components used to draw a circuit. Once the circuit file is created simulation command is given to simulate it and we get response according to schematic.

SPICE

SPICE is used when we need different kinds of analysis like AC analysis, DC analysis, DC transfer curve, noise analysis, transfer function analysis, transient analysis.
Instead of using breadboard for testing a circuit we use SPICE software it makes our work efficient.

DIGITAL VERSUS ANALOG CIRCUIT

Most of the electronic industry is comprises of analog and digital circuits both plays a crucial role in electronics and electrical applications.

Now there are some points, which defines there importance comparative to each other, are given as follows :

Continuity : Analog circuit functioned on continuous signal while in digital circuits operates on discrete signals.

Flexibility : Generally analog circuits lacks in terms of flexibility while digital circuits are highly flexible as   they can modified easily by just changing the logic function.

Complexity :  Analog circuits are more complex to design then digital circuits.

Converters :  In analog circuit there is no need of converters inputs and outputs both are given in analog   form while in digital circuits analog to digital converter is required for input and digital to analog converter is needed for output.

 Noise : Analog circuits are more vulnerable to noise while digital circuits have more noise tolerance.

Author - Jyotishna Bansal

(Intern at Silicon Mentor)

Different type of Transistor Logic Circuits

Logic Circuits:

Logic circuits play a vital role in designing digital electronics circuits. A logic circuit generates desired output on the basis of inputs applied and on the basis of rules which the corresponding gate follows. Logic Circuits include devices such as multiplexers, registers, ALU’s and Microprocessors. All these devices are designed using gates and gates are designed using transistors.

There are four categories in logic families:

RTL (Resistor Transistor Logic): RTL which is the first member of this family is not available in monolithic form. Such type of digital circuits are built using resistor as an input network and transistors are used for performing switching function. Advantage of using RTL is the use of minimum number of transistors but disadvantage is power dissipation is high when transistors are switched on.

DTL (Diode Transistor Logic): DTL is commercially available IC in 53/73 series. This class of digital circuit is direct forebear of TTL and in this gating function is performed by diode and transistor is used to perform amplifying function.

TTL (Transistor Transistor Logic): TTL is designed using resistors and BJTs. In this, gating function and amplifying function are performed by using transistors.

ECL (Emitter Coupled Logic): ECL belongs to non saturated class of digital logic family. In this current is forced between two terminals of an emitter coupled pair so sometimes it is called as Current Steering logic (CSL), Current Mode Logic (CML), Current Switch Emitter-Follower (CSEF) logic.

COMPARISON:

·     There is a disadvantage of high power dissipation in RTL circuits when transistor is switched on because of which high current is to be supplied and heat is generated inside the circuit. So to overcome these problems TTL circuits with Totem-Pole output are used.

·      TTL circuits are developed to provide higher speed and lower power dissipation for optimization of design. A TTL circuit has simplified design in comparison to other members of logic families and has high speed in comparison to RTL and easy design layout in comparison to ECL.

·        DTL has advantage of more fanout over RTL but propagation delay is relatively large.

·      In ECL each gate continuously draws current so it requires more power in comparison to other members of logic families.

  Author - Somya Bisaria

(Intern at Silicon Mentor)

 

Procedural Control Blocks in Verilog

There are two types of procedural blocks in Verilog: initial and always. These statements are the two basic statements in behavioral modeling. Both always and initial statement have separate activity flow. Each flow starts at simulation time 0.


Initial statement :  All statements inside an initial statement constitute an initial block. An initial block starts at time 0, executes once at time of simulation, and doesn’t execute again. If there are multiple initial blocks, each block starts to execute concurrently at time 0.


 Always statement : As it name indicates, it execute statements in always block continuously in a loop fashion. All behavioral statements inside an always statement constitute an always block and starts at time 0. An example is a clock generator module that toggles the clock signal every half cycle.
Example:
module clock_gen;
reg clk;
initial clk=0;
always #10 clk=~clk;
endmodule

PROCEDURAL ASSIGNMENT:
Procedural assignments update values of reg, integer, real, or time variable and cannot assign values to nets (wire data types).

Two types of procedural assignment statements:-

Blocking statement : These statements are executed in the order they are specified in a sequential block. In this, evaluation and assignment are done in a single step.

Example:
integer a=10,b=20,c=30;
 initial begin
 b=a+b;   //b=30   
 c=b;     //c=30
 end;

Non–blocking statement : In this evaluation and assignment in two steps. Firstly right hand side is evaluated immediately and secondly assignment to the left hand side is postponed until other evaluations which are currently going on are completed. A <= operator is used to specify non-blocking assignments.

Example:
integer a=10,b=20,c=30;
 initial begin
 b=a+b;    //b=30   
 c=b;       //c=20
 end;

Procedural Control Block (PCB)

Tags :          Procedural control Block,      PCB ,   FGPA,       ASIC,      HDL      VHDL

Author - Hemika Yadav

(Intern at Silicon Mentor)

What is HDL ?

Hardware description language (HDL) plays a vital role in very large scale integration (VLSI). HDLs looks much like a programming language C.  HDL   is textual description of an electronic circuit or  electronic chip.  In other words HDL is used  to describe hardware in terms of expressions and statements, control structures.  HDL is concurrent (all parts work at the same time)whereas traditional software is sequential. HDL is real time sensitive unlike software.  HDL  also allows for the compilation of an HDL program into a lower level specification of physical electronic components, such as the set of masks used to create an integrated circuit.

 HDL has ability to describe and simulate at behavioural, structural and mixed level. From above description we can say that HDL form an integral part of electronic design automation system,  specially for complex circuits such as microprocessor. Now we will know  more about HDLs. There are two types of HDL which is supported by IEEE. They are VHDL  ( Very high speed integrated circuit HDL) and Verilog HDL. These language are used in electronic devices that do not share computer’s basic architecture.

For high level modeling VHDL is  better while Verilog is better  for gate level modeling and switch level modeling. VHDL is not case sensitive while Verilog is case sensitive. Verilog is similar to C or PASCAL  language while VHDL is similar to ADA programming language in syntax. VHDL is more complex then  verilog. VHDL has the advantage of having a lot of constructs that aid in high level modeling. Verilog is easy to understand and easy  to  design. VHDL is different from Verilog in terms of signal assignment, interface declaration, in RTL assignment.  Verilog is much better then VHDL below the RTL level.  VHDL and Verilog is equivalent for RTL modeling. But the bottom line is that we should know both.

Verilog-HDL

Tags : HDL,  Verilog ,     VHDL ,     RTL ,     FPGA Vs ASIC ,  Verilog Training 

Author - Trisha Jain

(Intern at Silicon Mentor)

VLSI Training in Delhi NCR

VLSI training is the most important steps for the students who want to join VLSI industries or higher studies after B.Tech or M.Tech for the research and for those who want job in core electronics companies to settle their life. SiliconMentor has expertise and experience in the field of VLSI domain. Its expertise spans Verilog/SystemVerilog, FPGA, DSP using MATLAB, CMOS logic circuit, their RTL and circuit development, verification& layout using various tools. SiliconMentor targets the bridge between academics and industries because 90% graduates don’t have expertise in specific field and knowledgehow to enter in industries. So VLSI training is necessary to enhance and augment the knowledge in VLSI field. VLSI training has different modules for the different domains in VLSI such as Digital, Analogue, DSP, FPGA, Communication, Frontend and Backend design. In Frontend, we design RTL level and logic level blocks and their verification using Verilog/VHDL and SystemVerilog (tools like Modelsim and Questasim). A Netlist generates after the frontend design and their verification. This Netlist further propagates to the backend team for the circuit level and layout level design and verification using various tools like Cadence Virtuoso, Tanner (S-edit and L-edit), ADS, Cadence Orcad, P-Spice, H-Spice and Microwind. According to the training module, SiliconMentor gives you industries oriented training and also provides you different hand-on-project trainings. In India, two types of VLSI jobs available: 1st is in Frontend (Verilog design and verification) and 2nd in Backend (physical design automation). SiliconMentor makes you expertise in specific field to get your desired job.

VLSI Training in Delhi NCR

 Tags : VLSI Training in Delhi NCR,  MATLAB Projects Training in Delhi NCR , Verilog Training in Delhi NCR 

Author - Deepak Berwal 

(Research Associate at Silicon Mentor)